This invention relates to lubrication means for a machine and, more particularly, to means for providing a film of lubricant of sufficient thickness or depth upon the interior surface of a hollow rotatable shaft. This invention is particularly adaptable for use with power shafts and accessory drive shafts associated with gas turbine engines.
It is well accepted in the art to utilize the interior surface of a hollow rotating shaft to convey lubricant along the length of the shaft to bearings, drive connections or other mechanisms in need of lubrication. The centrifugal forces associated with the rotating shaft force the lubricant to adhere to the inner interior surface of the hollow shaft and, as more and more lubricant is applied to the shaft, the lubricant will spread out and migrate along the interior surface of the shaft. Where the mechanisms needing lubrication are located at the same diameter as the interior surface of the shaft, the lubricant will be conveyed into the mechanism. However, since the lubricant tends to form only a thin film on the interior surface of the shaft, mechanisms spaced radially inward of the interior surface, even by a small radial distance, will not receive the desired lubricant. This invention is directed toward providing lubricant to mechanisms located radially inward of the interior surface of the rotating shaft. The present invention achieves this accomplishment and yet is compatible with assembly and thermal expansion constraints which may be imposed by the structure and operating characteristics of the machine.
Therefore, it is an object of the present invention to provide lubricating means for delivering lubricant to the appropriate mechanisms of a machine. It is a further object of the present invention to provide means for lubricating a mechanism located radially inward of the interior surface of a rotating shaft.
It is yet another object of the present invention to provide lubricating means which are compatible with assembly and thermal expansion techniques associated with the machine.